Huh. I was actually assuming Kite, but the background is very... bright? That its a big odd / distracting.

Also when you do save for web. If you're in the save as JPG, slowly lower the quality one by one if you want to get the 'highest' quality below 20kb. Visually hard to differentiate, but still can do.
You should be able to see the preview and size in the window.